Tim, here is a method that a boatbuilder passed on to me when I was working on the Bambi. Trick is to hold the compass at the same angle while you are making your arch. If you look at my thread you will see pictures of the washer method. The boat builder add a post and gave me this method. It works great.
Don

Tim, here is a method that a boatbuilder passed on to me when I was working on the Bambi. Trick is to hold the compass at the same angle while you are making your arch. If you look at my thread you will see pictures of the washer method. The boat builder add a post and gave me this method. It works great.
Don

Norcal is righ, boat bulkheads are a harder to do, and a boat is never level. If you do a search for a tick stick it will also help to get the curve correct.

After all the suggestions presented here I opted for the Story Stick. I figured it would have the most chance of being success full for a rookie like me .

I ended up using a 5 gallon paint stick and trimed the end down to a point. I taped the paper on the bulkhead where I wanted my panel. You see a white panel there in the photo. That is the one I made that did not fit well enough for me.

Then I reproduced the story stick on my panel and cut it out. It fit much better. I could have made more story stick marks to reproduce it better, but the final product works good.

I think we can now all guess why Airstream used the aluminum channels around the curved bulk head edges (at least they did on my 1973 model). The channel must be something aproaching 3/4" deep. The bulkhead can then easily be cut to the same curve everywhere. It fits into the channel which then attaches to the wall. There can be a gap of at least 1/4" between the bulkhead and the wall that is effectively hidden by the channel. The gap amount can vary quite a bit too without it showing. I am sure that they intended this for another purpose too - namely to allow some flex at the intersection between the bulkheads and the wall but it does do a pretty good job of hiding the gap too while it is at it.

What I have done is similar to Royce . Find a plastic wheel from a toy or old pulley , about 2" diam , can be larger doesn't matter . Get your pattern material on the wall at least as close as the radius of the wheel . Put a pensil in ther center of the wheel and follow the contour of the wall . The wheel will keep the pensil mark a perfect 90 deg, from the wall . Now take the pattern down and add on enough material to the outer edge to make up the radius of the wheel . Then trace back holding the edge of the wheel on the original trace mark , this will put back the radius distance of the wheel , this then will give you the original wall line . Hope that made sense , it would take about 2 sec. to deminstrate .

You might want to try this 1.You'll need two sided tape 2. Starting on the outside top leave some tape overhanging then moving in on your curve follow the curve with the edge of your tape at the end your tape should follow the curve 3. Now peel the backing off attach paper to tape following the curve once tape is covered by paper grab the excess you left sticking out at the top and remove your template you now stick it to what you want to cut. I would suggest testing small pieces of different thickness of paper. Just a thought. The beauty is the paper doesnt have to be perfect you can trim it after along your tape .

You might want to try this 1.You'll need two sided tape 2. Starting on the outside top leave some tape overhanging then moving in on your curve follow the curve with the edge of your tape at the end your tape should follow the curve 3. Now peel the backing off attach paper to tape following the curve once tape is covered by paper grab the excess you left sticking out at the top and remove your template you now stick it to what you want to cut. I would suggest testing small pieces of different thickness of paper. Just a thought. The beauty is the paper doesnt have to be perfect you can trim it after along your tape .